Known are gear set arrangements which provide an overlay of the combustion engine and electric machine to create dedicated torques. As an example, the applicant names the EP 3165389 A1. In this, such overlay or interleaving, respectively, is shown. A transmission for a vehicle is presented with two, parallel partial transmissions configured as the main transmission, as well as with an output shaft, as well as two planetary gearsets which have elements like a carrier, sun gear, and a ring gear, whereby each partial transmission has a transmission input shaft, whereby a first transmission input shaft is designed as hollow shaft and a second transmission input shaft as solid shaft, whereby a second planetary gearset is positioned between an electric machine and the first transmission input shaft as a planetary stage. The electric machine is coupled to the sun gear of the planetary stage. The combustion engine is coupled to the ring gear of the planetary stage and the carrier of the planetary stage is designed as the drive for the downstream gearset. All shift elements of the main transmission are designed as claws.
When coupling the first transmission input shaft, the hollow shaft, while driving with the shift element I engaged in the EDA-mode, the following problem arises: the combustion engine is operated in any gear, for instance in the 7th gear, in which the shift elements D, G, and S are engaged. The shift element I is active and connects the combustion engine with the planetary stage. The hollow shaft is not connected with its then downstream gearset. The shift elements A, B, and C are disengaged or in neutral position, respectively. If now the hollow shaft needs to be connected to the downstream gearset to shift to another gear, one of the shift elements A, B, or C must be synchronized with the help of the electric machine. Through the connection to the combustion engine via the planetary stage, an effective torque (support torque) is created during synchronization of the rotational speed at the electric machine and then at the combustion engine which results in an unwanted change of the desired combustion engine rotational speed. The driver feels this as a slight jerk in the vehicle and this means a loss of drive comfort.
During the disengagement of the hollow shaft while driving in the EDA-mode, the following problem can occur with the support torque of the electric machine: the combustion engine is operated as a starting position in any gear, whereby the hollow shaft is connected with its downstream gearset, for instance in the 9th gear with the shift elements B, C, H, and S engaged. The shift element I is again active and connects the combustion engine with the planetary stage. The first transmission input shaft, the hollow shaft, is connected with its downstream gearset. If now the hollow shaft needs to be disconnected from its downstream gearset, the shift element B needs to be relieved of torque by means of the electric machine so that it can be disengaged. Through this connection to the combustion engine via the planetary stage, an active torque (support torque) is created by the electric machine at the combustion engine which causes a torque change at the transmission output. The driver notices that through a slide jerk in the vehicle and that means a loss of drive comfort.